This unusually large but (unfortunately) heavily restored parish church comprises a chancel, central crossing tower, transepts, S vestry and an aisled and clerestoried nave with N and W porches. The earliest part is the central tower (mid-12thc.), with transepts, which were either added or remodelled later in the same century. The nave and chancel date from the 13thc. and the W front was built in 1887.

Broadwater church was mentioned in Domesday Book, but the only remnant of that building might be the Anglo-Saxon doorway discovered in the S wall of the chancel during a restoration of 1936–39. Rectors are recorded from 1145, and the advowson descended with the manor until 1734.

The church was completely rebuilt, beginning in the third quarter of the 12thc. (1150s, 1160s) with the central tower. The tower has evidently suffered from instability, but the date of the rebuilding of the W arch is uncertain. According to Mayo that happened in the 14thc., and according to Harrison and Leeney, in the 18thc. (cf: Tortington chancel arch). Either seems possible. The church underwent numerous 'restorations' in the 19thc., in 1826, c.1830, c.1855, 1862-66 and 1887, but none of these schemes appears to have been well documented or understood. Around 1830 the tower was embattled and a beacon turret added. The newel staircase was filled up in the 1850s, and the turret removed in 1866. The chancel walls were straightened c.1855 by 'Mr Hide's experiment', but in 1866 it was heavily rebuilt and refenestrated. At the same time a vestry was erected on the site of the S transept chapels. The W front and W porch were erected in 1887.

The stonework of the tower arches is reputedly of Caen stone (not confirmed). The repertoire of motifs on the arches has led to comparisons with work at Old Shoreham and Steyning, although there are technical differences.

The authenticity of the capitals of the E arch should be questioned, although Harrison praised them very highly ('unsurpassed in craftsmanship by any work of their age') and maintained that only two, on the N side, had been renewed. Bond compared them with sculpture at Canterbury Cathedral, Reigate, New Shoreham and Chichester Cathedral, while Harrison pointed out parallels with Poissy, St Lomer de Blois and Burgundy. Harrison suggested that the craftsmen were influenced by Cluny, via Lewes Priory. There is nothing to support this allegation, either at Cluny or Lewes, and the most striking parallel is with sculpture of the 1160s and 1170s from the Ile-de-France. However, the crisp carving and smooth finish suggest the hand of a 19thc. restorer. The design of the inner arch capitals is particularly unconvincing. Each one is individually asymmetrical and unbalanced, but as a pair they attempt symmetry (across the arch, as it were) in a manner quite foreign to 12thc. sculpture (ie: their E sides match, but are quite different from the W sides, which also match).

Confusingly, while Harrison dated the arches to 1135-1160, he dated the E arch capitals to 1160-1200. Certainly if they are authentic, or copy original capitals, they would push the date of the arches into the 1170s, at the earliest.

The capitals of the bell stage of the tower are also untrustworthy. Some, carved with simple scalloped capitals, may be original or may copy originals, but the others have strange forms without parallel in 12thc. work. They may have been carved at the same time as the E arch capitals, perhaps during one of the early 19thc. restoration campaigns.

The lateral chevron of the tomb recess in the chancel is similar to that of some arches in the nave of Steyning, and the capitals carved into the impost band also finds parallels at Steyning, this time in the clerestorey.